Tree bracket fungi are a type of fungal disease that affects oak trees. They are caused by various species of the genus Ophiocordyceps (pronounced oh-pih-kee-KEEPS). These fungi produce mycelia which grow into the wood of the tree. The mycelium produces a substance called “bristle” or “brackish slime”. This substance causes damage to the bark and eventually results in death of the tree. There are several types of bracket fungus. Some are very small, while others cause severe damage to the trunk.
Bracket fungus is one of the most common fungal diseases affecting oaks worldwide. It is estimated that there are over 100 different species of bracket fungi and they affect all oak species from deciduous to coniferous trees.
The main symptoms include:
– Loss of foliage; leaves may turn yellow, brown or drop off completely.
– Leaf drop may occur at any time during the year.
– Leaves may die back prematurely due to lack of water.
In some cases, the affected tree will not show any signs of life after the first few years. Trees with large areas of dead branches and trunks are usually among those suffering from bracket fungus. Other symptoms include:
– Pitting or discoloration of bark and wood around infected areas.
– Gray or white fuzzy stuff near the base of the tree.
How did my tree get infected with bracket fungus?
There are several ways that your tree could have gotten infected with bracket fungus. One way is through an injury to the bark of the tree which allows the fungus to enter the tree and begin growing through the wood. Trees that have suffered physical damage such as collisions with cars or lawnmowers are more susceptible to the disease.
Another way for trees to get infected is when a tree already infected with the fungus falls on top of another tree. The weight of the falling tree can crush the bark of an uninfected tree, allowing the fungus to enter and grow inside the new tree.
Why is my tree infected with bracket fungus?
Although several types of fungi cause damage to the bark and wood of the tree, only a few really take advantage of the situation. Many types of fungi will actually take advantage of a tree that is already infected with a different type of fungus. This is called “colonizing” an already infected tree. Some types of fungus are also considered “opportunistic” meaning they don’t kill the tree right away, rather they slowly damage the tree over time.
How can I prevent my tree from getting infected with bracket fungus?
To prevent your tree from getting infected with bracket fungus, make sure it does not suffer any physical damage. If you notice that your tree has suffered physical damage then contact a professional arborist immediately. If you have recently injured your tree, wait a few weeks before applying a sealant or paint to the affected area, as this will help prevent the fungus from entering through the fresh wound.
If your tree is already infected with the fungus there are several things you can do to prolong the life of your tree. In most cases the fungus will not kill the tree right away, but rather it begins damaging the core of the tree over a period of years causing discoloration and death of branches. A good way to prevent further damage is to remove any dead or dying branches from your tree. This prevents the spread of fungus and opens up the center of the tree so it can receive more sunlight and access to water.
Another good practice is to ensure your tree has an even and constant supply of water. During the summer months the heat can cause trees to lose moisture at a much higher rate then you would during the cooler months. Be sure that your tree is always hydrated during the summer months, especially if you notice discoloration or a drop in foliage.
If you would like to have your tree treated for bracket fungus there are several products available at most garden centers. Most come in a liquid solution and are applied to the outside of the tree; all trees will require multiple treatments (every couple months) for a period of one to two years. These products are generally effective, although the fungus can become resistant to the treatment if not used properly. Always follow the instructions on the product when applying.
How do I prevent my tree from getting this disease again?
Once your tree has fully recovered from the infection there are several maintenance tasks you can perform in order to prevent a re-occurrence of the disease.
If your tree is outside it is recommended that you raise the base of the tree at least one foot above the soil surface. This will eliminate any contact with the soil, which could possibly carry over fungi or bacteria that could reinfect your tree. If your tree is already planted in the ground, try raising it by putting several pieces of wood under its base.
You should also mulch around the base of the tree. This will prevent competing plants from growing near the base of the tree and taking away vital nutrients and moisture.
It is also a good practice to prune your tree annually. Doing so will open up the center of the tree which allows for more sunlight and access to vital nutrients and water.
If you notice any discoloration or injury to your tree, make sure you address it immediately. The longer you wait to treat the tree, the further the disease will spread into the core of the tree.
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Signs of an infection
There are several signs that indicate your tree is infected with the anthracnose fungus. Some of these include:
Sunken brown discoloration can be seen on the top and bottom of the tree trunk. This indicates the rings of growth have been stopped by the disease.
Brown or black spots located on the leaves, branches, and even the fruit. The spots will begin to spread if left untreated.
Dead branches may begin to form on the tree. These will usually wither and turn a grayish color.
Small holes may begin to form in the fruit of the tree, these will then spread and turn into a brown or black discoloration.
If you notice any of the above symptoms on your tree it is important that you have the tree inspected by a Arborist to determine if it is indeed anthracnose. If the disease is found to be present, the Arborist can then prescribe a treatment plan in order to eliminate the fungus.
Contacting an Arborist
If you believe your tree to be infected with anthracnose, it is important that you have the tree inspected by an Arborist. The Arborist will be able to properly identify the symptoms and identify whether or not it is anthracnose. Once the disease is properly identified, the Arborist can then prescribe a treatment plan to eliminate the fungus from your tree.
Please call or email us if you would like to set up an appointment.
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This slideshow provides examples of signs your tree may have anthracnose. These photos are from a real infected tree in Ann Arbor.
Sources & references used in this article:
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Competition–colonization dynamics of spore‐feeding beetles on the long‐lived bracket fungi Ganoderma in New Zealand native forest by K Kadowaki, RAB Leschen, JR Beggs – Oikos, 2011 – Wiley Online Library
Beetle attraction to sporocarps and wood infected with mycelia of decay fungi in old-growth spruce forests of northern Sweden by T Johansson, J Olsson, J Hjältén, BG Jonsson… – Forest Ecology and …, 2006 – Elsevier
Is forest mushroom productivity driven by tree growth? Results from a thinning experiment by S Egli, F Ayer, M Peter, B Eilmann, A Rigling – Annals of forest science, 2010 – Springer
Fungal strategies of wood decay in trees by FWMR Schwarze, J Engels, C Mattheck – 2013 – books.google.com